Yen Sid is the powerful sorcerer in Fantasia, appearing as an old man with a long beard and robes that extended to the floor. The nickname ("Disney" spelled backwards) was given by Disney animators, as the sorcerer in "The Sorcerer's Apprentice" segment of Fantasia had no onscreen name, nor does the character in the original Goethe poem "Der Zauberlehrling", the inspiration for the music piece by Paul Dukas. Film historians believed Fred Moore added the same sized nose as Walt Disney's nose, and even added the same eyebrow length as Walt Disney's eyebrows.

Yen Sid serves as the sorcerer under whom Mickey Mouse is an apprentice. After executing a series of spells of summoning light out of a skull, changing its appearance as Mickey witnessed it while in the middle of his chores, Yen Sid decides to take a rest as he leaves his hat behind. From there, Mickey takes the hat and uses its magic to bring a broom to life to finish the chore of bringing water in from the well. However, Mickey does not know how to stop the magic now that it has been activated, and after he falls asleep, the entire basement is flooded. Thankfully, Yen Sid reappears, and uses his innate magical powers to recede the waters and undo the spell that caused the problem in the first place. From there, a disappointed (yet slightly amused) Yen Sid takes back his hat and broom and sends Mickey back to finish his chores after using the broom to send him off.

Yen Sid appears in the Disney/Square Enix video game series Kingdom Hearts, maintaining his role as Mickey's magical mentor with Donald Duck and Goofy showing him tremendous respect. The game series marked Yen Sid's first speaking role in his appearances prior, being voiced by Corey Burton in English, and Takashi Inagaki in Japanese. Yen Sid first appears in Kingdom Hearts II, based at his tower near Twilight Town. He is targeted to be turned into a Heartless by Pete, but thanks to Sora's efforts the Heartless never even get near him. Yen Sid enables Sora to once more know of the existence of Organization XIII, directing him to Flora, Fauna, and Merryweather who provide him with new clothes, as well as a new method to travel to worlds through routes opened by the Keyblade. He also gives the characters their Gummi Ship, which they had been without since the events of the first Kingdom Hearts. He disappears afterwards and is not encountered for the rest of the game, seemingly abandoning his tower, which becomes overrun with Nobodies. It is revealed in the video game prequel, Kingdom Hearts Birth by Sleep, that Yen Sid was once well versed in the Keyblade.

Yen Sid also appears in the Nintendo Wii title Epic Mickey as both its narrator (making him the only character in the game to have a spoken script rather than vocal effects as with all the other characters) and as the creator of a pen-and-paper world for all of Disney's forgotten creations to reside in including Oswald the Lucky Rabbit before Mickey's unintentional actions turn it into the Wasteland.

Media: Fantasia | Fantasia 2000 | Who Framed Roger Rabbit | Video game | House of Mouse | Kingdom Hearts

Shorts: Toccata and Fugue in D Minor | Nutcracker Suite | The Sorcerer's Apprentice | Rite of Spring | Intermission/Meet the Soundtrack | Pastoral Symphony | Dance of the Hours | Night on Bald Mountain | Ave Maria | Symphony No. 5 in C minor-I. Allegro con brio | Pines of Rome | Rhapsody in Blue | Piano Concerto No. 2 in F Major-I. Allegro | Carnival of the Animals, Finale | Pomp and Circumstance - Marches 1, 2, 3, and 4 | Firebird Suite - 1919 Version

Shorts from the Unfinished Third Fantasia: Destino | The Little Matchgirl | Lorenzo | One by One

Characters: Mickey Mouse | Donald Duck | Daisy Duck | Yen Sid | Chernabog | Chernabog's minions | Fairies | Hop Low and the Dancing Mushrooms | Dancing Flowers | Goldfish | Dancing Thistles | Magic Brooms | Tyrannosaurus Rex | Stegosaurus | Triceratops | Dinosaurs | Soundtrack | Bacchus | Jacchus | Centaurs | Centaurettes | Melinda | Brudus | Sunflower and her aides | Zebra Centaurettes | Fauns | Cupids | Iris | Apollo | Morpheus | Artemis | Pegasus and family | Zeus | Vulcan | Madame Upanova and her ostriches | Hyacinth Hippo and her hippos | Elephanchine and her elephants | Ben Ali Gator and his alligators | Monks | Butterflies | Bats | Humpback whales | Whale calf | Whale calf's parents | Duke | Rachel | Flying John | Killjoy Margaret | Jobless Joe | George Gershwin | Tin Soldier | Ballerina | Jack-in-the-Box | Rats | Yo Yo Flamingo | Snooty Flamingos | Noah | Animal couples | Spring Sprite | Elk | Firebird

Interstitial Hosts: Deems Taylor | Leopold Stokowski | Steve Martin | James Levine | Itzhak Perlman | Quincy Jones | Bette Midler | James Earl Jones | Penn & Teller | Angela Lansbury

Objects: Yen Sid's hat

Locations: Yen Sid's tower | Bald Mountain | Graveyard | Mount Olympus | New York City

Vehicles: Noah's Ark

Songs: Ave Maria